Buoyant roller boat



'Aug. 13, 1935. J. FITZGIBBON BUOYANT ROLLER BOAT Filed Aug. 20, 1934 2 Sheets-Sheet l JOSE PH F 7'Z GIBBO/V INVENTOR A TTORNEY 1935. J. FITZGIBBON 2,011,045

BUOYANT ROLLER BOAT Filed Aug. 20, 1934 2 Sheets-Sheet 2 INVENTOR A TTORNEY Patented Aug. 13, 1935 UNITED STATES PATENT OFFICE BUOYANT ROLLER BOAT 1 Claim.

This invention relates to improvements in boats wherein buoyant propellers are employed. With boats having a hull immersed in the water, there is a great deal of sliding friction and the higher the speed of the boat, the greater the friction and the greater the resistance is to forward movement offered by the water.

An object of. this invention is to provide a buoyant boat in which the rolling friction of rotary multiple keels or rollers is substituted for the sliding friction of a hull having a single fixed keel.

Another object of this invention is to provide a buoyant boat wherein the hull is supported upon cylindrical buoyant propellers which have sufficient displacement to maintain them together with the superimposed weight of the boat mostly above the surface of the water when at rest, and to raise the boat above the water when in motion.

I Another object of this invention is to provide a buoyant boat embodying buoyant cylindrical propellers mounted in outboard bearings on opposite sides of the hull adjacent the bow and a buoyant cylinder mounted in outboard bearings at the stern, all of the said cylinders being rotatable about horizontal axes transverse to the direction of travel of the boat.

Another object of this invention is to provide a buoyant boat embodying buoyant cylindrical propellers rotatably mounted on opposite sides of the hull adjacent the bow and having thereon oppositely directed'helical propelling blades so formed as to drive the water away sideways from the hull and exercise a centralized raising action on the bow end of the boat when the propellers are rotated.

With the above and other objects in view, the invention will be hereinafter more particularly described and the combination and arrangement of parts will be shown in the accompanying drawings and pointed out in the claim which forms -part of this specification.

Reference will now be had to the drawings, wherein like numerals of reference designate corresponding parts throughout the several views, in

Figure 3 is a cross-sectional view, the section being taken as on line 3--3 in Figure 4.

Figure 4 is a plan view of the buoyant boat.

In the illustrated embodiment of the invention, the several views show a buoyant boat l com;

prising a hull ll having a buoyant cylinder l2 rotatably mounted outboard in bearings l3 behind the stern I4, and two buoyant cylindrical propellers 15, respectively positioned on opposite sides of the hull I 1 adjacent the how [6.

The propellers l5 have been secured to a driv-- ing shaft ll extending transversely through the hull. The propellers l5 comprise buoyant cylinders l8 having helical blades l9 attached at one edge of the outer faces of the cylinders l8 and project outwardly therefrom. The propeller blades IS on the respective cylinders 18 face in opposite directions with respect to the hull II and drive the water away sideways from the hull, and when the propellers are rotated, the blades l9 produce a lifting effect which causes diminished immersion sufficient to raise the hull above the water. The propellers l5 are rotatably mounted in bearings 20 and 2|, best shown in Figure 3.

The cylinder l2 at the stern and the cylinders l8 at the bow are hollow and act as buoyant floats which are partly immersed in the water. The fiotative power of the cylindrical floats should be sufiicient to maintain the hull l I mostly above the surface of the water when at rest, and to raise the hull out of the water when in motion so that the only resistance to motion of the hull is that ofiered by the air.

As shown in Figures 2 and 4, the hollow buoyant cylinder l2 has corrugations 22 on its cylindrical surface, the said corrugations being positioned parallel with the axis of said float and provide a more positive means to cause rotation of the cylinder l2 when the boat i0 is set in motion by the action of the propellers l5.

Under operating conditions, the rudder diverts or throws the water in an inclined direction rearwards of the boat. As best shown in Figure 2, the buoyant rear cylinder i2 has conically shaped smooth surfaced ends, the pointed smooth surfaced ends permit the diverted water to move along an inclined surface on the float and get away from the boat. The pointed ends thus serve to facilitate steering of the boat.

Rotary motion may be imparted tothe driving shaft I1 and the propellers 15 by means of an engine 23 which may be provided with a pinion gear 24 meshing with a gear 25 mounted on the shaft ll. As shown in Figure 1, a rudder 26 at the stem end of the boat extends downward and a rudder post 21 is provided at its upper end with a steering arm 28 for actuating the rudder. As shown, the rudder 26 is interposed between the QQW and stem floats.

It is to be noted that two or more helical blades may be mounted on each buoyant cylinder l8; the said blades extending from one end face of a cylinder to the other end face, but only around one half the circumference of the said cylinder.

The bearings 2| for the buoyant propellers I5 are supported from outboard frames 29 and the bearings I3 for the buoyant cylinder l2 are supported from an outboard frame 30. It will be noted that the large transverse distance between the ends of the propellers I5 tends to augment the stability of the boat and enables greater speeds to be reached in safety in boats of small or very large capacity.

I claim:

In a buoyant float-supported boat of the class described, comprising two buoyant cylindrical propellers secured to a driving shaft extending transversely through the hull, said shaft being mounted in outboard bearings, said propellers be 1 ing on opposite sides of the hull at the bow, said propellers including oppositely directed helical propelling blades extending around one-half the circumference and co-extensive with the length of said cylinders, said propeller blades being designed to drive the water away transversely from opposite sides of said hull and automatically exert an augmented centrallized raising action sufficient to raise the bow end of said boat above the water when in motion, a rudder at the stern end of said boat, a buoyant cylindrical float rotatably mounted in outboard bearings rearward of said rudder, said stern float having corrugations positioned. in its cylindrical surface and parallel with its axis, said rear float having conically smooth surfaced ends to facilitate steering, the axes of all said buoyant cylinders being horizontal to permit said cylinders to rotate in the direction of travel of said boat, and means for rotating said propeller shaft.

JOSEPH FITZGIBBON. 

